Alkyl perfluoroalkylene amidates



United States Patent 3,544,618 ALKYL PERFLUOROALKYLENE AMIDATES EdwinDorfman and William E. Emerson, Grand Island, N.Y., assignors to HookerChemical Corporation, Niagara Falls, N.Y., a corporation of New York NoDrawing. Filed Aug. 17, 1967, Ser. No. 661,240 Int. Cl. C07c 103/14 U.S.Cl. 260-482 8 Claims ABSTRACT OF THE DISCLOSURE New alkylperfluoroalkylene amidates of the formulae HzNfi (CF2)x-(|'JOCnH2u+1where x is from 1 to 12, n is from 1 to 25, and A is aryl substitutedmethyl of 7 to 21 carbon atoms, are produced either (a) by treatmentwith ammonia or a corresponding dialkyl perfluoroalkylene dicarboxylate,or (b) by treatment of the imide of the perfluoroalkylene dicarboxylicacid with a corresponding alcohol. They are useful intermediates in thepreparation of perfluoroalkylenetriazine polymers.

This invention relates to new compositions of matter classified as alkylperfiuoroalkylene amidates of the formulae:

where x is from 1 to 12, n is from 1 to 25, and A is arylsubstitutedmethyl of from 7 to 21 carbon atoms. The compounds are prepared either(a) by treatment with ammonia of the corresponding dialkylperfluoroalkylene dicarboxylates or (b) by treatment of the imide of theperfluoroalkylene dicarboxylic acid with the corresponding alcohol. Anexample of a dialkyl perfluoroalkylene dicarboxylate is dimethylperfluoroglutarate which was prepared by A. L. Henne and W. J.Zimmerscheid, J. Am. Chem. Soc., 67, 1235 (1945). Another example isdimethyl perfluorosebacate which was prepared by treatment ofperfluorosebacoyl chloride with methanol, and recovering the diester byvacuum distillation: B.P. 120- 122 at 4 mm. Perfluorosebacoyl chlorideB.P. 115-7 at 36 mm., was prepared from the acid in 86 percent yieldusing a fourfold quantity of thionyl chloride, ethyl acetate as solvent,and a catalytic amount of pyridine. Perfluorosebacic acid andperfluorotetradecanedioic acid are known compounds described by I. L.Knunyants et al., Proc. Acad. Sci. USSR, 129, 328 (1959) and I. L.Knunyants and M. N. Krasuskaya, Bull. Acad. Sci. USSR, 1963, 190.Dipropyl perfluorosebacate was prepared from perfluorosebacic acid,n-propyl alcohol and a catalytic amount of sulfuric acid. The by-productwater of reaction was removed by distillation of the propylalcohol-water azeotropic mixture. The dipropyl perfiuorosebacate had aboiling point of 125-128 centigrade at 5 millimeters of mercury pressure(absolute). Diethyl difluoromalonate or dimethyl difiuoromalonate may beproduced by the method of C. E. Inman, -R. E. Oesterling, and E. A.Tyczkowski, J. Am. Chem. Soc., 80, 6533-5 (1958). Perfiuoropimelic acid,perfluoroazelaic acid and perfluorononanedioic acid may be made byelectrolytic fluorination of the corresponding hydrocarbon acids by themethod of Guenther, US. Pat. No. 2,606,206, which gave perfluorosebacicacid. The esters of these acids can be made by the procedures used forthe preparation of the perfluorosebacic acid esters described above.Examples of imides are perfluorosuccinimide and perfluoroglutarimide,which were prepared by the method of A. L. Henne and W. F. Zimmer, J.Am. Chem. Soc., 73, 1103 (1951). Other homologous perfluoroalkanedioicacid imides may be prepared by this process when the correspondingperfluoroalkanedioic acid amides are used as starting materials.

Illustrative compounds embraced by this invention are:

methyl perfluoroglutaramidate (where x=3) ethyl perfluoroglutaramidate(where x=3) n-propyl perfiuoroglutaramidate (where x=3) isopropylperfluoroglutaramidate (where x=3) n-butyl perfluoroglutaramidate (wherex=3) benzyl perfluoroglutaramidate (where x=3) methylperfluorosebacamidate (where x=8) n-propyl perfluorosebacamidate (wherex=8) methyl difluoromalonamidate (where x=1)methylperfluorosuccinamidate (where x=2) methyl perfluoroadipamidate(where x=4) methyl perfluorosuberamidate (where x=6) methylperfluorotetradecanamidate (where x=12) The alkyl perfluoroalkyleneamidates of this invention are useful intermediates in the preparationof perfluoroalkylene triazine polymers, such as those disclosed incopending application Ser. No. 533,430, filed Mar. 11, 1966. Thesepolymers are thermally stable and resistant to some solvents, whilebeing soluble in other solvents, such as alkyl acetates, alkylperfluoroalkanoates, and fluorinated solvents, such as fluorinatedxylenes and fluorinecontaining triazines.

TREATMENT WITH AMMONIA When the compounds of this invention are preparedby treatment with ammonia of a corresponding diester of a perfluorinateddicarboxylic acid, the reaction is carried out in a substantiallyanhydrous medium.

It is preferred to use a solvent, such as methylene chloride, benzene,toluene, xylene, or ether. However, a solvent may not be necessary,especially if an excess of diester is used as the solvent. It is to beunderstood that a heel of monoester product may also be used as asolvent for the reaction.

The temperature of the reaction should be between about 78 and aboutdegrees centigrade. The preferred temperature range is between aboutminus 30 and about 30 degrees centigrade.

The reaction can be carried out at atmospheric pressure; however,pressures above and below atmospheric pressure may also be used.

Agitation during the reaction is preferred in order to avoid formationof localized by-products. One by-product to be minimized is thecorresponding perfluoroalkylene diamide.

In general the mole ratios of ammonia to diester should be in a rangebetween about 0.2 and about 0.7, with the preferred range being between.about 0.35 and 0.5.

'It is preferred to add the ammonia to the diester, especially in orderto avoid the formation of by-products such as the corresponding diamide.This by-product formation is also minimized by operating at lowerconversions by using less than molar equivalent amounts of ammonia.

Any perfluoroalkylene diamide formed as a by-product in the reaction,can be used as such, or can be converted to the corresponding dinitrilefor use in polymerizations, or can be converted to the correspondingperfluoroal'kylene diacid for recycle back into the process as thecorresponding perfluoroalkylene diester. The perfluoroalkylene diamidemay also be converted to the imide which can be converted to theproducts of this invention through the imide route described herein.

IMIDE TREATMENT In accordance with this invention the compounds claimedherein can also be produced by treatment of imides ofperfluoroalkanedioic acids of the formula:

where x is as defined above, with an alcohol of the formulae C H OH andAOH where n is from 1 to 25 carbon atoms and A is aryl substitutedmethyl of 7 to 21 carbon atoms and recovering the product so produced.

The temperature range for this reaction is between about zero and aboutthe reflux temperature of the reactants. This upper temperature is overabout 100 degrees centigrade.

The reaction can be carried out at atmospheric pres sure. However,pressures above and below atmospheric pressure may also be desirable.

A solvent is not required in conducting the reaction. However, an inertsolvent, such as benzene, can be used.

Agitation is not required for eifecting the process, however it ispreferred. The reactants can be added in a number of ways, and it isunimportant in what order they are added. They can also be addedsimultaneously.

The reactants may be added in equivalent amounts. It is generallypreferred however to use a slight molar excess of the alcohol over theimide.

It is important that this reaction be conducted under substantiallyanhydrous conditions in order to avoid hydrolysis and formation of otherbyproducts.

Whether using the ammonia treatment route or the imide route to obtainthe products of this invention, the claimed compounds are recovered fromthe crude reaction mixture by distillation, by recrystallization of theproduct, or by solvent extraction of the impurities from the crudeproduct. Where high purity is not required, it is preferred to strip olfthe excess alcohol which may be present in the reaction medium andrecover the product as the residue.

Of the two methods described herein for producing the compositions ofthis invention, the cyclic imide route is preferred where the cyclicimide itself is readily available, because the reaction goes relativelyeasily with excess alcoholor equivalent amounts of alcohol, andespecially because essentially one product is formed. However, the

formation of the compound from the diester is preferred where thecyclicimide is not readily available or may be more expensive than thediester.

This invention is further illustrated in the examples below, whereintemperatures are in degrees centigrade and parts are by weight.

Example 1 28.47; H, 1.99; N, 5.53. Found (percent): C, 28.40; H,.

In a similar manner, by substituting perfluorosuccinimide (3.93 grams,0.023 mole), for the perfluoroglutar- 4 imide used in the abovereaction, methyl perfiuorosuccinamidate can be obtained.

Example 2 Ethyl perfluoroglutaramidate-In a manner after Ex-- ample 1ethyl perfluoroglutaramidate was produced from perfluoroglutarimide andethanol. The product had a boiling point of 98 degrees centigrade atabout 0.09 millimeter mercury.

Analysis.-Calculated for C7H7F6NO3 (percent): C, 31.47; H, 2.64; N,5.24. Found (percent): C, 31.45; H, 2.53; N, 5.35.

Example 3 n-Propyl perfluoroglutaramidate-In a manner after Example 1n-propyl perfluoroglutaramidate was produced from perfluoroglutarimideand n-propanol. The product had a boiling point of 108 degreescentigrade at 0.17 millimeter mercury.

Analysis-Calculated for C H F NO (percent): C, 34.17; H, 3.23; N, 4.98.Found (percent): C, 34.17; H, 3.41; N, 5.05.

Example 4 iso-Propyl perfluoroglutaramidate.-In a manner after Example 1iso-propyl perfluoroglutaramidate was prepared from perfluoroglutarimideand iso-propanol. The product had a boiling point of 5 degreescentigrade at 0.1 millimeter mercury.

Analysis.--Calculated for C H F NO (percent): C, 34.17; H, 3.23; N,4.98. Found (percent): C, 34.30; H, 3.34; N, 4.95.

Example 5 n-Butyl perfluoroglutaramidate.1n a manner after Example 1n-butyl perfluoroglutaramidate was prepared from perfluoroglutarimideand n-butanol. The product had a boiling point of 118 degrees centigradeat 0.5 millimeter mercury.

Analysis.-Calculated for C H F NO (percent): C, 36.62; H, 3.75; N, 4.75.Found (percent): C, 36.79; H, 3.68; N, 4.96.

Example 6 Benzyl perfluoroglutaramidate.1n a manner after Example 1benzyl perfluoroglutaramidate was prepared from perfluoroglutarimide andbenzyl alcohol. The product had a melting point of between 61 and 62degrees centigrade (from toluene).

Analysis.Calculated for C H F NO (percent): C, 43.78; H, 2.76; N, 4.26.Found (percent): C, 43.61; H, 2.57; N, 4.28.

Example 7 Methyl perfluorosebacamidate.To dimethyl perfluorosebacate(252 grams, 0.48 mole), in methylene chloride (700 milliliters), wasadded ammonia (5.8 grams, 0.34 mole), at between about 25 to about 29degrees centigrade. The mixture was stirred for 7 hours. Crude methylperfluorosebacamidate (110 grams) was obtained at 100 degrees centigradeat 0.25 millimeter mercury. This product was recrystallized from toluenewhich gave white crystals (61 grams) with a melting point of between and116 degrees centigrade.

Analysis.-Calculated for C H F NO (percent): C, 26.26; H, 1.00; N, 2.78.Found (percent): C, 26.13; H, 1.06; N, 2.84.

In a similar manner by substituting dimethyl perfluorosuberate (201grams, 0.48 mole), for the dimethyl perfluorosebacate used in the abovereaction, methyl perfluorosuberamidate can be obtained.

In a similar manner, by substituting methyl difluoromalonate (81 grams,0.48 mole), for the dimethyl perfluorosebacate used in the abovereaction, methyl difluoromalonamidate can be obtained.

In a similar manner, by substituting methyl perfluoroadipate (152.5grams, 0.48 mole), for the dimethyl perfluorosebacate used in the abovereaction, methyl perfluoroadipamidate can be obtained.

Example 8 n-Propyl perfiuorosebacamidate.To di-n-propylperfluorosebacate (115 grams, 0.2 mole) in methylene chloride (150milliliters) was added ammonia (2.21 grams, 0.13 mole) in a reactionflask equipped with a Dewar condenser at minus 78 degrees centigrade andwith a magnetic stirring bar. When the ammonia was consumed, thereaction mixture was subjected to distillation at atmospheric pressureto remove the methylene chloride, then under vacuum at one millimetermercury to remove unreacted ester. When solidified product appeared inthe condenser the distillation was stopped, and the n-propylperfluorosebacamidate containing some perfluorosebacamide was recovered.

Although this invention has been illustrated by citing specific detailsof given species embraced within the scope of this invention, it is tobe understood that various modifications within the invention arepossible, some of which have been referred to above. For instance, alkylperfluoroetheralkylene amidates may be made. These compounds have theformulae:

o Nmr lolocmwmmiioa where m is an integer of from 0 to 12, n is aninteger of from 1 to 25 carbon atoms, and A is aryl-substituted methylof 7 to 21 carbon atoms,

where p is an integer of from 2 to 12 and n and A are as defined above,

0 Nmi (c Fz)mC F20 (OF 01% ,0 F (5001mm o 11m (ommomo (CF 0 Fa0) CF(")OA 0 NHri JoF(ooF20m ocmwromiioonmnfl and o Nnziior (001m F),0CF2(CF2)mC 0A where y is an integer of from 0 to 100, and p, m, n and A areas defined above and Z Z Z Z where v plus t is an integer of from 0 to100, and p, 'm, n and A are defined above, and

where n and A are as defined above In each of the above formulae Z isselected from the group consisting of fluorine and CF Illustrativecompounds embraced by this process are:

methyl 3-oxaperfluorosuberamidate methyl3-oxaperfluoro-2-methylpimelamidate methyl3,9-dioxaperfluoroundecanedioic acid amidate methyl3,6,9,12-tetraoxaperfluorotetradecanedioic acid amidate Other compoundsembraced by this process are alkyl amidates of branchedperfluoroalkylene dicarboxylic acids such as the following illustrativeexamples:

Other starting materials embraced by this inventor are haloalkylperfluoroalkylene dicarboxylates of the formula:

LCHZO? (CF91? OCHzr.

which comprises treating a perfluoroalkylene imide of the formula:

with an alcohol selected from the group consisting of C H OH and AOH, atapproximately equimolar amounts, from about 0 C. to about refluxtemperatures of the reactants, and recovering the products produced,

wherein n is from 1 to 25, A is aryl substituted methyl of 7 to 21carbon atoms, and X is from 1 to 12.

2. The process of claim 1 wherein the alcohol employed is of the formulaC H 0H, where n is from 1 to 25.

3. The process of claim 1 wherein the alcohol employed is AOH, where Ais aryl substituted methyl of 7 to 21 carbon atoms.

4. The process of claim 3 wherein the alcohol employed is benzylalcohol.

8. The process of claim 2 wherein the alcohol employed is butanol.

References Cited UNITED STATES PATENTS 2,502,478 4/1950 Padbury et al260482 2,523,470 9/1950 Kropa et a1. 260-482 XR 2,794,012 5/1957 Tawney260482 X'R 5. The process of claim 2 wherein the alcohol employed mLORRAINE A, WEINBERGER, Primary Examiner is methanol.

6. The process of claim 2 wherein the alcohol employed is ethanol.

7. The process of claim 2 wherein the alcohol employed is propanol.

PAUL JOHN KILLOS, Assistant Examiner

